1. Field of the Invention
This invention relates generally to the harvesting and treating of agricultural crops and relates particularly to the method and apparatus for harvesting and treating tobacco in an efficient economical manner.
2. Description of the Prior Art
In the past flue cured bright leaf tobacco has been harvested one leaf at a time as the leaves matured on the plants and several leaves were oriented so that the stems were all located in the same general area and were bound together to form a hand. A plurality of hands were placed on a stick and a plurality of sticks were placed in a barn where such leaves were subjected to heat for curing.
The harvesting and treating of tobacco leaves has been hard back-breaking labor which often involved entire families and groups of families working together. The leaves of most tobacco plants mature from the group up over a period of from four to six weeks and it was necessary for each plant to be inspected periodically so that the mature leaves could be removed while the immature leaves remained on the stalk to continue developing. This obviously necessitated many passes through the field in order to harvest all of the usable tobacco leaves.
Many efforts have been made by individuals, manufacturing companies and several colleges and universities to ease the task of harvesting and treating tobacco leaves by reducing the labor and drudgery involved as well as to increase the efficiency of the operation and make the operation more economical. Initially harvesting machines were developed which transported workmen through the tobacco fields and permitted workmen on the lower portions of the machine to prime mature leaves so that other workmen could bind the leaves together in hands and place the hands on sticks for curing within the tobacco barns. Some examples of this type of structure are disclosed in the U.S. Pat. No. to Long 2,952,370 and 3,215,288.
More recently bulk harvesting of the tobacco leaves became practical in which the tobacco leaves were placed in a random haphazard manner within a tobacco rack of a height less than the length of a mature tobacco leaf and such racks were placed in two or three tiers within a tobacco barn for curing. Some examples of this type of structure are the U.S. Pat. No. to Long 3,233,339; and Hassler U.S. Pat. No. 3,105,713, 3,110,326 and 3,251,620.
With the advent of the bulk curing rack, automatic defoliating harvesters were developed which automatically removed tobacco leaves within a predetermined range above the ground as the harvesters moved through the tobacco fields. Such defoliators were adjustably mounted on the harvesters so that several passes through the tobacco field could be made at spaced intervals of time and with the defoliators located at different elevations so that substantially all of the usable tobacco leaves were removed from the stalks. Some examples of this type of harvester are the patents to Wilson U.S. Pat. Nos. 2,816,411, 2,834,175 and 3,083,517; Suggs et al U.S. Pat. No. 2,834,174; Splinter U.S. Pat. No. 3,093,949; Pickett et al U.S. Pat. No. 3,507,106; and Long U.S. Pat. No. 3,834,137.
Recently the South Carolina Agricultural Experiment Station at Clemson University in Clemson, South Carolina, has developed a technique for growing low profile tobacco. In this technique, the growth of tobacco plants is controlled and the upper portion of each tobacco plant is topped or removed so that substantially all of the tobacco leaves remaining on the stalk mature at substantially the same time whereby all of the leaves left on each stalk can be harvested simultaneously.
In order to grow low profile tobacco and to extend the harvesting season over approximately a six week period, one third of the tobacco plants usually are of an early variety and are planted at one time, a second third of the tobacco plants are of a mid-season variety which are planted later than the early variety, and the last third are of a late variety which are planted after the second third. After the plants have attained a height of approximately 30 inches, the top 6 inches is removed to leave a stalk substantially 24 inches high. Thereafter by controlling the amount of fertilizer and other plant nutrients approximately one-half of the first third are caused to mature at the same time and the other half of the first third are caused to mature approximately one week later. The first half of the second third is caused to mature approximately one week after the first third and so on through the entire tobacco crop whereby a portion of the crop matures each week for approximately six weeks which is the normal harvesting period for tobacco leaves.
In order to harvest low profile tobacco, Alphin and Pitner of Clemson University developed a tobacco harvester which was granted U.S. Pat. No. 3,695,014 that simultaneously removes all of the leaves remaining on a tobacco stalk so that the harvester makes only one pass by each individual tobacco stalk. Even though the tobacco plants have been topped, the remaining leaves reach a stage of development such that they yield approximately 85% as much tobacco as conventionally grown plants.